Prepaid mobile services represent optional services that a mobile subscriber can access and pay for with a pre-established account. For example, a cellular telephone user or a wireless palm-top computer user may pre-establish an account with his service provider in order to pay for his subsequent access to voice and/or data services such as teleconferencing, music downloading, specialized web content accessing, etc.
In the prior art, a request for a prepaid mobile service (i.e., a mobile service that is charged based on usage against a pre-established account) must be approved in advance before the mobile subscriber is allowed to access the requested prepaid mobile service. For example, if a mobile subscriber requests to download a particular song that costs $2.00 into his cellular telephone, the request must be authorized in advance before the mobile subscriber is allowed to access the downloading site to download the requested song.
In the prior art, when a mobile subscriber sends a prepaid mobile service authorization request (SAR) to request access to a particular service, the SAR is fully processed before authorization is granted or denied. Full processing typically involves looking up the subscriber status (e.g., whether the subscriber has established a prepaid account), rating the service request (e.g., determining the cost associated with fulfilling the request), determining subscriber balance sufficiency (e.g., whether the balance in the subscriber's prepaid account is sufficient to pay for the requested service), and storing transaction data (e.g., to ensure that the subscriber's account is only charged once if the server happens to crash in the middle of service rendering).
It has been found, however, that the full processing of the SAR introduces a substantial delay between the time the SAR is issued by the subscriber and the time an authorization response (e.g., authorize or deny) is received. Although some of the aforementioned delay is due to the inherent latency through the data network and particularly through the voice network, a substantial portion of the delay is attributable to the requirement that the SAR be fully processed before an authorization response can be issued. In some cases, 4 seconds or more may pass before the mobile subscriber receives a response to the SAR, of which 1 to 2 seconds or more may be attributable to the full processing of the SAR.
Full processing of the SAR takes a non-trivial amount of time since each processing step may involve a different third-party application program and may also involve accessing a different specialized database. For example, looking up the subscriber status may involve accessing the subscriber repository management application, which may further involve accessing a subscriber database. As another example, rating the service request may involve accessing the service rating application, which may further involve accessing a service cost database. As yet another example, determining subscriber balance sufficiency may involve accessing the billing application, which may further involve accessing a billing database. Each of these processing steps may involve a latency in the range of 200 milliseconds to 1.5 seconds, for example.
For subscribers conditioned to expect an immediate response to a service request (such as the immediate response experienced when a service request is issued through a browser program on a desktop computer, for example), the lengthy delay between the time a SAR is sent and the time an authorization response is received may be deemed unacceptably long by some. Some of these subscribers may, as a response, choose not to bother with the prepaid mobile services in the future due to the perceived lengthy delay, thereby resulting in a loss of potential revenue for the providers of such prepaid services. Other subscribers may express their dissatisfaction by switching to other mobile service providers, particularly if they perceive, rightly or wrongly, that the delay is the fault of their current mobile service providers.
As a response to customer complaints, some mobile service providers have adopted a “hot billing” approach to processing SARs. When a “hot billing” mobile service provider receives any SAR, authorization is granted immediately, and the requesting subscriber may immediately begin using the requested service. Concurrently, the SAR is processed to obtain an authorization confirmation. If the authorization confirmation is a negative (e.g., if the requesting subscriber has an insufficient account balance to cover the requested service), the service that is already under way is terminated. On the other hand, if the authorization confirmation is positive, the subscriber is allowed to continue to use the service already authorized.
However, many types of service can be completed in the short time it takes to perform the full processing of the SAR. In other words, by the time a “negative” authorization confirmation is ascertained, the requested service may have been completed already. Because of this loophole in the hot billing approach, some dishonest subscribers have been able to fraudulently obtain certain services over and over without having to maintain an adequate account to pay for those services.
Furthermore, hot billing may also alienate some credit-worthy but honestly mistaken subscribers. For example, some otherwise honest and credit-worthy subscribers may, through a misunderstanding or because of an honest mistake, inadvertently request a service that costs more than the remaining balance in their prepaid account. Pursuant to hot billing, such a subscriber may experience an abrupt termination of a requested service after usage has begun. The abrupt termination may unduly annoy such a subscriber, causing that subscriber to be dissatisfied with and to possibly terminate his service with the mobile service provider. As a result, the mobile service provider may lose potential revenue and/or may lose an honest and credit-worthy subscriber, precisely the type of subscriber that most mobile service providers wish to acquire and retain.